The present invention relates to industrial fasteners and more particularly to those industrial fasteners which are used to removably secure two panels. The panels may be flush mounted service or enclosure panels which are readily opened and closed. For example, one panel may be the door of a domestic automatic washing machine and the other panel its door frame. The fastener of the present invention is particularly well suited for assembling curved sheets such as engine cowlings or flat sheets such as access panels and may accommodate slightly misaligned holes in the panels to be joined.
At the present time a number of industrial fasteners are commercially available which releasably secure two panels. Many additional types of such fasteners have been proposed in prior patents. Generally such fasteners will operate and lock only when the panels to which they are fastened are completely joined or almost completely joined.
Generally, industrial fasteners of this type consist of two separate members each of which may be attached to an individual panel. One panel might be a machine wall or frame to which the receptacle member is attached. The other panel might be the service, inspection or enclosure panel to which the stud member is attached. Panel attachment by this type of fastener provides for tight, easily perfected seals, which additionally are easily released to provide for quick access to the enclosure.
Fasteners of this type comprise a stud member which acts in combination with a receptacle member having retention jaws. As described in U.S. Pat. No. 2,562,056 to O. E. Norberg et al and U.S. Pat. No. 1,302,390 to A. J. Lobar, a cylindrical stud engages the receptacle jaws irrespective of the stud rotational disposition. Disengagement of the stud member from the receptacle member is accomplished by exerting an outwardly directed pulling force on both the stud and the receptacle as the stud is rotated back and forth.
U.S. Pat. No. 3,718,950 to J. B. Engstrom discloses a fastener which comprises a notched stud member having a turn member head which is encased in a spring-biased socket. The stud member is held against the receptacle jaws by spring tension. Rotation of the stud produces a cammed broadening of the receptacle jaws, enabling the stud to be withdrawn.
U.S. Pat. No. 2,552,006 to C. P. Sorensen and U.S. Pat. No. 2,486,003 to D. Christensen disclose fasteners whose stud noses are rectangular in cross-section. In Christensen externally tensioned receptacle jaws hold the stud in combination with the receptacle and in Sorensen the stud is held by spring flanges. Rotation of the stud disengages the stud from the jaws, permitting the stud to be separated from the receptacle. In the Sorensen patent the serrated stud grooves contact the receptacle jaws, thus suspending inadvertent rotational stud movement (col. 4, lines 8-12). Additionally the chamfered stud nose aids in stud-receptacle alignment. Similarly the Christensen patent discloses a tension spring and manual pull cord combination which prevents the stud from rotationally disengaging the receptacle jaws, while a compression spring holds the stud vertically against the receptacle jaws.
The presently available commercial fasteners are satisfactory for many purposes; however, there is a need for a rugged, easily operable, self-aligning fastener which permits partial closure of panels in a locking position and is relatively inexpensive to produce and install.